OBJECTIVE To investigate if long-acting insulin analogs decrease the risk of diabetic ketoacidosis (DKA) in young individuals with type 1 diabetes. RESEARCH DESIGN AND METHODS Of 48,110 type 1 diabetic patients prospectively studied between 2001 and 2008, the incidence of DKA requiring hospitalization was analyzed in 10,682 individuals aged </=20 years with a diabetes duration of >/=2 years. RESULTS The overall rate of DKA was 5.1 (SE +/- 0.2)/100 patient-years. Patients using insulin glargine or detemir (n = 5,317) had a higher DKA incidence than individuals using NPH insulin (n = 5,365, 6.6 +/- 0.4 vs. 3.6 +/- 0.3, P < 0.001). The risk for DKA remained significantly different after adjustment for age at diabetes onset, diabetes duration, A1C, insulin dose, sex, and migration background (P = 0.015, odds ratio 1.357 [1.062-1.734]). CONCLUSIONS Despite their long-acting pharmacokinetics, the use of insulin glargine or detemir is not associated with a lower incidence of DKA compared with NPH insulin.